Cutter and cutter holder for taps



Aug.- 30, 1932. s NEWMAN 1,874,586

CUTTER AND CUTTER HOLDER FOR TAPS Original Filed April 25, 1927 Fig.5.

3mm Samuel [Newman Patented Aug. 30, 1932 UNITED STATES PATENT OFFICE SAMUEL IE. NEWMAN, F WAYNESBORO, PENNSYLVANIA, ASSIGNOE TO LANDIS MA- CHINE COMPANY, OF WAYNESBORO, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

CUTTER AND CUTTER HOLDER FOR TAPS Original application filed April 25, 1927, Serial No. 186,470. Divided and this application filed February 12, 1931. Serial No. 515,366.

This invention relates to thread cutters for taps and to means for holding them and particularly to thread cutting devices for collapsible taps and is a division of my application Serial No. 186,470, filed April 25, 1927, for collapsible taps.

An object of the invention is to provide new and improved thread cutters which recede during the process of cutting a thread and with new and improved holders for such cutters.

Another object is to provide removable thread producing cutters in which separable holders are provided so as to eliminate the necessity of providing new Working or sliding surfaces on the cutters themselves.

In constructions heretofore known the thread cutting chaser was in sliding contact with one of the taper producing elements in the tap so that the seating surfaces of the chaser become worn and hence soon failed to produce accurate threads. An OlOJGCt of the present invention is to eliminate such defects so that the life of the chasers will be increased and more accurate threads produced.

A still further object is to provide new retracting means for the chaser or cutters and means for collapsing the chasers when thread of the desired length has been cut.

3 Further objects and advantages will become apparent as the description proceeds.

Referring to the accompanying drawing, which is made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a longitudinal section of a tap showing the thread cutting elements, holders and plunger mounted therein,

Figure 2 is a face view of a tap showing the cutters and holders in assembled position,

Figure 3 is a front view of one form of holder,

Figure 4, a side view of the same,

Figures 5 and 6 are front and side views respectively of the chaser or cutter used with the holder shown in Figures 3 and 4,

Figures 7 and 8 are front and side views respectivel of a modified form of chaser holder, ant;

Figures 9 and 10 are front and side views respectively of the chaser used in holders shown in Figures 7 and 8.

In the drawing numeral 10 indicates the bodyportion of a tap having a removable head 11 secured thereon, as by means of bolts 12. The head 11 is provided with radial slots 13 in which are'positioned radially movable thread cutting devices 14. Within the body portion 10 is axially slidable a plunger 15 having ahead 16 removably secured thereto by means of a bolt 17. The bolt is threaded at its forward end in the head 16 and has an enlarged end 18 seated in a socket in the end of the plunger 15 and held in said socket by means of a spring 19. A front plate 20 is held on the head 11 by means of bolts 21.

The'head 16 is provided .with'slots having tongues 22 around which engage correspond ing slots 23 of chaser holding blocks'24. The holders 24 are likewise provided with projections25 having surfaces 26 upon which the cutters 1d are seated. A tongue 28 extends in from a back portion 29 of the holder which tongue engages in a slot 30 in the back of the cutter. The cutter is held against radial movement by means of the tongue 28. As will be seen. from the assembled view of Figure 1 there is no relative axial movement between the cutters 14 and the holders 24, the holders and'cutters are, however, positioned radially by means of the cam surfaces 31 on the end of the head portion 16. Since there is no relative movement between the cutters and holders there will be no wear on the engaging surfaces.

. In Figures, 7 to 10 inclusive are shown modified forms of holders 32 and cutters 33. In this form the base 34 of the holder engages the beveled portion 31 of the head 16 and the tongue 22 of the head engages the slot 35 of the holder. There is provided, how ever, a tongue portion 36 which cooperates with the surface 37 of the holder and holds the cutter in position. The upper back portion 38 of the holderis threaded at 39 and the cutter 33 has its back cutout as shown at 40 to receive a screw 27 which serves to hold the cutter against outward or radial movement. With the holders and cutters shown in Figures 7 to 10 inclusive the cutters 3;?

may be removed and replaced Without removing the end plate 20. This provides a. simpler means of assembly. The plunger 15 is controlled by the work coming in contact with a plate 41 which plate controls radial position of a slide 42 as is more fully described in the parent application at which this is a division.

In operation the pliinger is moved to v the right as the ring 41 contacts with the work 43. This movement to theright grad.- ually retracts the cutters 14 as the inner beveled edges of the holders slide on the corresponding beveled portions 31 of thei-heatl 16. This positions the chaser to cut the dem sired taper on the thread; Byrotating the bolt 17 as by means of a wrench inserted inthe hexagonal socket 44 the radial position of the cutters 14 maybe varied toadj usti them fon-workof different diameters. With the forms of cutters and holders shown in F ig ures 7' to 10 in order to replace the" cuttersscrews 27 may be removed after which the cutters may be lifted out of their holders 32,

after Whichthe cutters-may be slid axiall'y ofi'the holdersand new ones positibnedithera on. In botlrforms of cutters and holdersthere is no relativeaxial sliding between the cutters and the holders, consequently the engaging; surfaces are not worn; It will be obvious to thoseskilled in art: that various changes mayhemade inr my device without departingfronr t'hespii'itfi of the invention and therefore I do not limit" myself to What is shown inthe drawihgjand" desciihedin the specification, but. only as indicat'ed hy the appended claim. 1

Having thus fully described my said in?" i'ention, what I'cl'aim asnew and desire t0: secuieby Letters Patent, is:

lnacollapsible tapin-combinatio'n', a-chasei" holder-and a chaser, the chasenhavingpar:- allelcutting serrations; on one face and a' cut away portion; in theopposite face to provide a tongue anda chaserholderhavin'g two-parallel extending 'ribs of-unequal length w and a groove therebetween-forreceiving said? tongue the longer of said ribshaving a threaded opening extending throughthe pe riphery of the tap longitudinally of said longer riband at an angle to the bottomofi said groove, and a screw threaded through said opening and engaging a' notch iii-the chaser to secure it' to the holder, substan tially as set forth.

In witnesswhereof, I' have hereunto" set/ nivhandat W'aynesboro, Pennsylvania, this ninthday of" February, A D; nineteen'hundred and thirty-one;

' SAMUEL F..N-EWM'ANI and new ones positioned therein. VWith the{ cutters and holders showniir Figures 3 to 6- inclilsive it is necessary to remove thepl'ate' 

